


Human Experimentation

by TigerMultiverse



Series: Straw Hat Kaiyo [7]
Category: One Piece
Genre: Angst and Hurt/Comfort, Blood and Injury, Blood and Torture, Blood and Violence, Emotional Hurt/Comfort, Fanart, Gen, Human Experimentation, Hurt/Comfort, M/M, Medical Experimentation, Medical Torture
Language: English
Status: In-Progress
Published: 2020-05-08
Updated: 2020-05-08
Packaged: 2021-03-01 18:21:58
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence
Chapters: 1
Words: 3,257
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23701501
Author URL: https://archiveofourown.org/users/TigerMultiverse/pseuds/TigerMultiverse
Summary: While stopping for supplies, the navy kidnap Kaiyo on the command of an admiral, but the reason is not yet know, but Kaiyo will know soon...Will the Straw Hats be able to save her? Or will they need help from an unlikely ally?
Relationships: Kaiyo Garden (OC) & Monkey D Luffy, Kaiyo Garden (OC) & Mugiwara Kaizoku | Strawhat Pirates, Kaiyo Garden (OC) & Vinsmoke Sanji, Roronoa Zoro/Vinsmoke Sanji
Series: Straw Hat Kaiyo [7]
Series URL: https://archiveofourown.org/series/1544869





	Human Experimentation

A simple lamp lit the darkroom, a middle-aged man sat at an office desk as he stared at a picture in front of him. It was a wanted poster.

A knock came to the door and the man told them to come in, in walked a marine who saluted before speaking. “Sir, the troops are ready to head out!” He said.

“Good.” The man hummed, not taking his hard eyes off the image.

“Sir, if I may ask. Who are we capturing?”

The man hummed again as he picked up the poster and turned it around for the marine to see it. “We’re going after this girl.” He said as if stating a simple fact, knowing that the marine's face was slightly pale.

“Uh, p-pardon me by asking this sir, but, why do we need her?” He stuttered.

“Because if we can harness her powers, then we can make our marines stronger against pirates like the Straw Hats.” The man said, leveling the marine with a hard and cold look, which made him straighten up. “Now, get going!”

“Yes sir, Admiral Sakazuki!” The marine saluted one last time before closing the door.

Sakazuki, or the Admiral Akainu, sighed and placed the poster down on his desk, looking at it for a long while. “Enjoy your peace while it can, because soon, it will all be broken, and you'll never see your Nakama again,” he narrowed his eyes at the poster. “Straw Hat Kaiyo.”

Akainu glared at Kaiyo’s recent bounty, the words **‘ONLY ALIVE’** bold and not on a lot of pirate bounties.

Soon, that bounty won’t be worth anything with what he has planned with the pirate girl.

* * *

It was a clear, bright sunny day or afternoon. Puffy white clouds littered the blue sky as they drifted on. The afternoon sun shines down on a nice little village bustling with activity. People walking around, working at the docks, children playing, the marketplace almost packed with villages and pirates.

The Straw Hat pirates docked a couple of minutes ago and we’re going on a simple supply run.

It would just take a few minutes, but of course, Luffy wanted to look around and so did Kaiyo.

Morgan didn’t want them going off on their own, or Luffy getting them into trouble like he always does, but Nami said that it wouldn’t harm anyone and they could shop without Luffy getting in the way.

But Morgan was still a little reluctant to let them go off.

“It’s fine Morgan, we're just gonna explore a bit,” Kaiyo assured the alchemist.

Luffy then bent down so his head was between the girl's legs and swiftly lifted her onto his shoulders, prompting her to laugh and hold unto her captain as he smiled.

“Shishishi! Don’t worry so much Morgan!” Luffy smiled childishly, holding onto Kaiyo’s scared legs.

“I have a right to worry, considering the fights you get into.” Morgan pointed out, lifting an eyebrow. “Besides we're not gonna be here for long-“

“We’ll be quick!” Kaiyo cut her off. “We just wanna look around.”

Morgan looked at her young Nakama and idiot captain for a moment before sighing in defeat. Kaiyo was making her puppy dog face that always made her bend to the little girl's will.

_Goddamn it._

“Okay fine.” Morgan groaned, before opening her eyes again and pointing a finger at Kaiyo. “But make sure he stays out of trouble, and be back in a few minutes.”

“We’ll be fine Morgan, I’ll keep an eye on him.” Kaiyo lifted her hand, palm facing the sky. “Don’t worry so much.”

Morgan almost glared when Kaiyo repeated Luffy's words but kept her face indifferent as she watched them walk further into the village and disappear in the crowd. “Ugh, I’m gonna regret this later.” Morgan groaned, shoulders slumping as she almost imagined the possible mess that Luffy could cause.

“Morgan-Kun! Can you please carry this bag?” Nami called the alchemist, who walked over to the navigator and took the bag she was gesturing to.

“Do you believe he won’t get into trouble?” Morgan asked, glaring ahead as the two walked back to the rest of their Nakama.

“Not really, but Kaiyo’s with him so it shouldn’t be so bad.” The redhead smiled and walked ahead of Morgan.

“Right.” Morgan deadpanned, unconvinced that Luffy wouldn’t start something.

Morgan and Nami met back up with their Nakama, being Zoro, Sanji, Chopper, Robin and Usopp, the rest we’re back at the ship, and they continued shopping. As they went from stand to stand, Morgan felt herself relax as the tension left her body and their shopping continued.

Seeing Zoro and Sanji bicker also helped her relax, especially when Zoro would flirt with Sanji and make the cook flush red.

And when some people, like Zoro or Usopp, did something stupid prompting Nami to hit them over the head always helped to make Morgan’s day.

It’s all very amusing.

About 30 minutes later, they were almost done with shopping, and Kaiyo and Luffy should be heading back now. The Straw Hats were packing up their supplies when Morgan felt a slight pressure at the back of her head. At first, she pegged it as nothing, but then the pressure became harder and she knew it was her Concentration Haki warning her. Quickly turning around and allowing her Haki to slow the world down around her, she saw a marine pointing his rifle at her head. Morgan clapped her hands and pressed them to the gun, catching the marine by surprise, and deconstructed it, making the gun fall apart.

“MARINES!” Morgan yelled to her crew, pulling the marines arm roughly and hit his head with her elbow, knocking him out. The Straw Hats quickly looked over to see more marines come out from behind the buildings and vendor stands, swords drawn and guns loaded.

The Straw Hat pirates readied themselves for the oncoming fight and charged.

Limbs appeared and broke marines backs, three swords slashed chests and sprayed blood, deadly legs broke bones and dented the earth floor, a large body punched and threw marines left and right, walls were made with a clap and spark of lightning, storm clouds formed above and zapped marines, and a large slingshot pulled back and fired plant-like ammo at the oncoming soldiers.

The fight seemed to drag on longer than normal, but that didn’t mean the Straw Hats were beaten. These marines obviously knew how to hold out against them, and how to fight pretty well, the pirates were already covered in cuts and bruises.

One marine managed to surprise Morgan and swung his sword at her, the alchemist raised her arm to defend herself while jumping back, the marines sword missing her head by a mile but deeply cutting her arm. Morgan retaliated by punching the marine in the head then grabbing him by his shirt and throwing him towards a group of marines, knocking them off their feet.

Eventually, Morgan and Nami pressed back to back as they took down enemies left and right with their respective staffs.

“Where’s Luffy and Kaiyo?!” Nami yelled out to Morgan, sending out a storm cloud and electrocuting multiple marines.

“They went off into the village!” Morgan replied as she swiped at multiple marines and transmuted a wall and sent them into the air.

“Someone has to go after them-” Nami was cut off when a bulky marine with brass knuckles rammed into her and Morgan into the ground. The alchemist sat up and wiped the blood away from her mouth as she glared up at the marine bastard.

“We have to deal with these bastards first.” Morgan sneered as she stood up and transmuted metal gauntlets around her forearms and hands. “Besides, those two can handle themselves.”

* * *

Meanwhile, the Straw Hat captain and his young Nakama had wandered pretty far into the village, giving polite hello’s to the passing villagers.

The day was very beautiful, and Kaiyo was glad that it was pretty quiet and uneventful. The girl smiled as she placed her head atop Luffy's fluffy raven locks and looked up at the beautiful blue sky and plush white clouds. Sometimes she wished that more days were like this while fighting pirates and marines along with exploring new islands were exciting and a great adventure, Kaiyo still liked the days that were quiet and relaxing where she could have fun with her Nakama and be with them.

Kaiyo must have zoned out because when she refocused she saw that Luffy and she were a bit deeper in the village, and she realized that they should head back now.

But before she could say anything, Luffy suddenly stopped and tensed up.

The captain reached up and grabbed Kaiyo, gently lowering her down to the ground before he turned around and that’s when Kaiyo’s Haki kicked in and marines popped out from behind the houses with swords and rifles.

Just as soon as they arrived, they attacked with a war cry.

Swords clashed with Armament Haki and bullets were fired and dodged. Luffy and Kaiyo easily fought the marines, the latter sometimes going off to protect the villagers from getting hurt. As they fought, some marines managed to scrape and bruise the two pirates but that didn’t stop them.

Since they weren’t that tough, Luffy didn’t need to use his 2nd Gear. The Straw Hat captain had a hard look on his face as he dodged and punched marines left and right. Luffy then wrapped his stretched arms around a bunch of marines and spun them around a couple of times before throwing them at a group of marines a few feet away. Then he turned around and punched a marine in the stomach and sent him flying into a wall. Three marines aimed their rifles at Luffy and fired a few times, making the bullets go through the man before they were bounced back and hit the marines.

Kaiyo’s marks and eyes glowed blue as she punched and kicked incoming marines into walls and the ground, leaving broken bones and bleeding lips and noses. One marine with a sword charged her and clumsily swiped his sword at her, but Kaiyo just dodged with ease and took the sword from the marine, since she left her own on the Sunny. Then with fluid movements and a firm form she learned from Zoro, Kaiyo began slashing at the marines.

The fight dragged on for some time, it was like the marines just kept coming, but Luffy and Kaiyo weren't getting tired in the least.

They were just getting started.

During the fight, Kaiyo unknowingly began to drift further away from her captain. When she did notice, she was about to call out to him when her Observation Haki went off as she suddenly felt the presence of someone behind her.

Turning around, she saw a navy admiral in a dark blue suit underneath the large admiral jacket laying over his shoulders, his skin was average and he had brunette hair, she couldn’t see his eyes because the cap he was wearing was shadowing his expression. Kaiyo could sense an aura of danger around this man, but before she could take a step back the admiral reached out with crazy speed and grabbed Kaiyo, tugging her into his arms and holding tightly, preventing her from freeing her arms or kicking him.

“Oi! Let go of me!” Kaiyo yelled as she tried and failed to struggle out of the admiral's hold. It was clear that he was stronger than her.

“We have her! Retreat!” The admiral yelled out to the marines, who nod and run in the direction of their ship.

“Let go! Let me go!” Her cries fell on death ears as the admiral began to walk into an alley. With a cry of desperation, she calls out for her captain. “LUFFY!”

The cry of his young Nakama draws Luffy’s attention from the fleeting marines as he turns and sees Kaiyo being taken into a dark alley by an admiral. “Kaiyo!” He yelled as he ran after them into the alley.

There, the admiral stands at the end of it with a struggling and distressed Kaiyo in his arms.

“Straw Hat Luffy,” He says in destaining.

“Give her back you bastard,” Luffy growled as he glared at the admiral.

“I’m afraid I can’t do that Straw Hat Luffy.” The admiral says with a monotone voice it makes a rage bubble in Luffy's chest. “This child is highly needed for the marines.”

After that was said, a mass of black and purple built up behind the marine and started to swirl around him. Briefly, Kaiyo realized that it was a teleportation devil fruit power, and the admiral had begun to walk into it!

“NO! Let go of me!” Kaiyo tried to get out of the admiral's hold but he was too strong, she only managed to get one arm out of the hold.

“NO!” Luffy ran to them, arm outstretched for his Nakama. **“KAIYO!”** He yelled desperately as she and the admiral began to disappear into the dark mass.

Kaiyo stretches out her free arm to her captain with wide eyes filled with fear. **“LUFFY!”** She cried as everything began to get darker.

Luffy was almost there, almost had her!

He was so close!

He was…so…

The Straw Hat captain stumbled forward as he was met with empty air. Panting, a bit disoriented and confused, Luffy turned and saw that it was only him in the alley. Kaiyo…was gone…she was _gone_ …that admiral took her…

Luffy seemed to be in a daze as everything processed in his mind, his chest hurt and he felt something he hasn’t felt since he was a kid, since Ace died.

_Helplessness…_

Rage suddenly burst in his scared chest as he clenched his fists tightly and screamed in anguish.

He failed his Nakama, he couldn’t save her.

He couldn’t save her!

How…how can he be the King of the Pirates if he can’t protect his crew? If he can’t save them…

_...dammit…_

_Damnit..._

**“DAMNIT!”**

* * *

A marine surprised Morgan and managed to knock her to the ground, the alchemist slightly dazed as she pushed herself up in her arm and looked up to see the marine raise his sword in the air and prepare to bring it down on Morgan.

Reflexively, Morgan brought an arm up to cover her head from the sword.

Great, was this how she died? On the ground cowering?

As Morgan prepared for her seemingly death, the marine's arm had just begun coming down when a gloved hand firmly stopped the marine.

“Stop.”

Morgan looked up in confusion and saw the marine look in stare at who stopped him. It was a woman about the same age as her, with pale skin and bags under her eyes and a scar under her left one, mismatched gold and silver eyes, dark hair with red highlights, wearing a black hoodie with brown pants, light grey gloves, and red and black shoes. Morgan couldn’t tell if she was a marine or pirate since the woman wasn’t wearing anything that said she was with the navy.

“We’re done here, go back to the ship.” The woman said to all the marines firmly as she let go of the marine's arm.

“Y-yes Lieutenant Hiro!” Some marines said as they saluted the woman and rushed to their ship at the docks, some having to help others walk or carry them.

Morgan stared in confusion at the woman before realization of who the woman was sunk in.

_She was at Marineford two years ago..._

__

She had been at the battle of Marineford two years ago, when Morgan, Luffy, and the Whitebeard pirates had arrived to save Ace. Hiro hadn’t been fighting, she was just off to the side watching, with an expression that Morgan couldn’t quite read.

Like now, the woman, Hiro, was staring at her with an unreadable expression.

Before Morgan could dwell on it for too long, Hiro cast one final look to the pirates before turning and calmly walking back to the ship with her gloved hands shoved into her pockets.

Morgan panted as she sat up and looked around.

The Straw Hats stared in confusion as each of them either got up from the ground or calmed their rapidly beating hearts.

Chopper was the least injured of them all, so the little doctor quickly got to work in checking on his Nakama and treating their wounds. Robin had started using her limbs to help villages who had been caught in the fight to stand and lift the destroyed stands off of them. Usopp helped Nami stand up and lean against one of the intact food stands.

“Is everyone alright?” Morgan asked, still sitting on the ground.

“Do we look alright?” Zoro sneered. The swordsman was tending to Sanji as he helped the cook stand in his slightly shaking legs.

“Screw you,” Morgan said curtly.

The alchemist was about to say something else when she caught the sight of someone walking towards them. Morgan strained her magenta-violet eyes to try and see who was coming towards them. When they got closer, she finally saw who it was.

It was Luffy, and…he was alone.

_What?_

“Luffy?” Morgan stood as her captain came closer. The boy didn’t say anything as he just kept walking.

There was definitely something wrong. Luffy's hair was shadowing his eyes and he was covered in scrapes and bruises. And there was this aura around the captain, Morgan couldn’t place it.

His straw hat wasn’t in his head but hanging from its thread on his back and...wait, where was Kaiyo?

“Luffy?” Nami and Usopp called to their captain as he walked past his Nakama and stopped, his back towards them as he stayed still and silent.

“Wait, where’s Kaiyo?” Sanji asked, concerned when he finally noticed that the young girl wasn’t there.

The Straw Hat captain didn’t answer, just stayed standing there eerily still as his Nakama grew worried about his silence. He’s never like this, yes he goes to be alone and will go quiet sometimes, but not like this, and not with this aura around him. The silence seemed to drag on for hours when it was actually just a couple minutes when Luffy finally spoke.

 _“...they took her.”_ He said.

…

At that moment it felt like the Straw Hat pirate's hearts stopped in pure horror.

Everything felt so cold and their breaths came in and out short and fast, panic rising through them as the seconds dragged onto minutes.

“Those bastards took her.”

Tears brimmed in Sanji’s eyes as he started shaking, which made Zoro bring the cook into his arms and hold him firmly against his broad chest. Nami had also started shaking and Usopp continued to hold her up, the sharpshooter's face was drawn in shock. Chopper was also frozen with shock, his eyes blank as he stared at Luffy. Robin was the same, an unreadable expression on her face and her arms and dropped from their position at her chest and hung limp at her sides. Morgan was...in shock to say the least. Her body felt numb and the world stopped, and she hasn’t felt this way since her father died.

The pirates stayed there for a long time, a feeling they never felt aside from the shock and horror and fear coursed through them, it was excruciatingly painful and they never knew they would have this feeling.

The feeling that they _lost…_

They failed...


End file.
